Clinical value of liquid biopsy in FGFR2 fusion-positive cholangiocarcinoma patients during targeted therapy.

PURPOSE: FGFR2 fusions occur in 10%-15% of intrahepatic cholangiocarcinoma (iCCA) patients, potentially benefiting from FGFR inhibitors (FGFRi). We aimed to assess the feasibility of detecting FGFR2 fusions in plasma and explore plasma biomarkers for managing FGFRi treatment. EXPERIMENTAL DESIGN: We conducted a retrospective study on 18 patients with iCCA and known FGFR2 fusions previously identified in tissue samples from prior FGFRi treatment. Both tissue and synchronous plasma samples were analyzed using a custom hybrid capture gene panel with next-generation sequencing (VHIO-iCCA panel) and validated against commercial vendor results. Longitudinal plasma analysis during FGFRi was performed. Subsequently, we explored the correlation between plasma biomarkers, liver enzymes, tumor volume, and clinical outcomes. RESULTS: Sixteen patients (88.9%) were positive for FGFR2 fusion events in plasma. Remarkably, the analysis of plasma suggests that lower levels of circulating tumor DNA (ctDNA) are linked to clinical benefits from targeted therapy and result in improved progression-free survival and (PFS) overall survival (OS). Higher concentrations of cell-free DNA (cfDNA) before FGFRi treatment were linked to worse OS, correlating with impaired liver function, and indicating compromised cfDNA removal by the liver. Additionally, increased ctDNA or the emergence of resistance mutations allowed earlier detection of disease progression compared to standard radiological imaging methods. CONCLUSIONS: VHIO-iCCA demonstrated accurate detection of FGFR2 fusions in plasma. The integration of information from various plasma biomarkers holds the potential to predict clinical outcomes and identify treatment failure prior to radiological progression, offering valuable guidance for the clinical management of patients with iCCA.

Early-Stage Breast Cancer Detection in Breast Milk.

Breast cancer occurring during pregnancy (PrBC) and postpartum (PPBC) is usually diagnosed at more advanced stages compared with other breast cancer, worsening its prognosis. PPBC is particularly aggressive, with increased metastatic risk and mortality. Thus, effective screening methods to detect early PrBC and PPBC are needed. We report for the first time that cell-free tumor DNA (ctDNA) is present in breast milk (BM) collected from patients with breast cancer. Analysis of ctDNA from BM detects tumor variants in 87% of the cases by droplet digital PCR, while variants remain undetected in 92% of matched plasma samples. Retrospective next-generation sequencing analysis in BM ctDNA recapitulates tumor variants, with an overall clinical sensitivity of 71.4% and specificity of 100%. In two cases, ctDNA was detectable in BM collected 18 and 6 months prior to standard diagnosis. Our results open up the potential use of BM as a new source for liquid biopsy for PPBC detection. SIGNIFICANCE: For the first time, we show that BM obtained from patients with breast cancer carries ctDNA, surpassing plasma-based liquid biopsy for detection and molecular profiling of early-stage breast cancer, even prior to diagnosis by image. See related commentary by Cunningham and Turner, p. 2125. This article is featured in Selected Articles from This Issue, p. 2109.

A pan-cancer clinical platform to predict immunotherapy outcomes and prioritize immuno-oncology combinations in early-phase trials.

BACKGROUND: Immunotherapy is effective, but current biomarkers for patient selection have proven modest sensitivity. Here, we developed VIGex, an optimized gene signature based on the expression level of 12 genes involved in immune response with RNA sequencing. METHODS: We implemented VIGex using the nCounter platform (Nanostring) on a large clinical cohort encompassing 909 tumor samples across 45 tumor types. VIGex was developed as a continuous variable, with cutoffs selected to detect three main categories (hot, intermediate-cold and cold) based on the different inflammatory status of the tumor microenvironment. FINDINGS: Hot tumors had the highest VIGex scores and exhibited an increased abundance of tumor-infiltrating lymphocytes as compared with the intermediate-cold and cold. VIGex scores varied depending on tumor origin and anatomic site of metastases, with liver metastases showing an immunosuppressive tumor microenvironment. The predictive power of VIGex-Hot was observed in a cohort of 98 refractory solid tumor from patients treated in early-phase immunotherapy trials and its clinical performance was confirmed through an extensive metanalysis across 13 clinically annotated gene expression datasets from 877 patients treated with immunotherapy agents. Last, we generated a pan-cancer biomarker platform that integrates VIGex categories with the expression levels of immunotherapy targets under development in early-phase clinical trials. CONCLUSIONS: Our results support the clinical utility of VIGex as a tool to aid clinicians for patient selection and personalized immunotherapy interventions. FUNDING: BBVA Foundation; 202-2021 Division of Medical Oncology and Hematology Fellowship award; Princess Margaret Cancer Center.

Expression of TILs and Patterns of Gene Expression from Paired Samples of Malignant Pleural Mesothelioma (MPM) Patients.

MPM is an aggressive disease with an immunosuppressive tumor microenvironment, and interest in exploring immunotherapy in this disease has been increasing. In the first line of treatment, the combination of nivolumab and ipilimumab demonstrated an improvement in survival over chemotherapy. The presence of TILs has been recognized as a marker of antitumor immune response to chemotherapy in solid tumors. The aim of our study is to identify the effect of treatment on immune cells and the immune gene profile in MPM. We investigated the changes in expression of TILs in 10 human MPM paired tumor tissues using immunohistochemistry and gene expression analysis from paired untreated and treated samples. In this small series, we demonstrated that during the evolution of disease without any treatment there was an increase in the inflammatory component in tumor samples. After systemic treatment there was a decrease in the number of TILs. We observed that after systemic treatment or disease progression immune gene signatures were suppressed. Our integrated analysis of paired samples with immune profile and genomic changes on MPM suggested that during the evolution of the disease the immune system tends to switch, turning off with treatment.

Timeless protection of telomeres.

The DNA replication machinery encounters problems at numerous genomic regions that are inherently difficult to replicate. These genomic regions include telomeres, which contain repetitive DNA and telomere-binding proteins. If not properly regulated, replication of such genomic regions can result in DNA damage, leading to genomic instability. Studies implicated a role of Timeless-related proteins at difficult-to-replicate genomic regions, including telomeres. However, how these proteins maintain telomeres was elusive. In a recent report, we described the role of Swi1, a Timeless-related protein, in telomere maintenance in fission yeast. We demonstrated that Swi1 is required for proper replication of repeat DNA sequences at telomeres. We also showed that Swi1-deficient cells utilize recombination-based ALT (alternative lengthening of telomeres)-like mechanisms to maintain telomeres in the absence of telomerase. Here, we highlight these findings and present additional data to discuss the role of Swi1Timeless in telomere protection and ALT prevention.